The present invention relates to a process cartridge, an assembling method therefor and an electrophotographic image forming apparatus.
Here, the electrophotographic image forming apparatus forms an image on a recording material through an electrophotographic image-formation type process. Examples of electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (a laser beam printer, an LED printer or the like), a facsimile machine and a word processor.
The above-described process cartridge contains as a unit an electrophotographic photosensitive member and a charging means, a developing means or a cleaning means in the form of a cartridge that is detachably mountable to a main assembly of an image forming apparatus. The process cartridge may contain an electrophotographic photosensitive member and at least one of a charging means, a developing means and a cleaning means in the form of a cartridge that is detachably mountably to a main assembly of an image forming apparatus. The process cartridge may contain an electrophotographic photosensitive member and at least developing means in the form of a cartridge that is detachably mountably to a main assembly of an image forming apparatus.
With a process cartridge type apparatus, the servicing or maintenance operations can be in effect carried out by the users, so that the operativity is significantly improved, and therefore, the process cartridge type is widely used in the electrophotographic field.
As shown in FIG. 23, the process cartridge 45 comprises a developing device frame 43 supporting a developing roller 18 and a toner accommodating container 46, which are welded with each other by ultrasonic welding. To the developing unit, a cleaning frame 47 which supports a photosensitive drum 11, a charging roller 12 and a cleaning blade 14, is coupled by a pin 49. A compression coil spring 42 is provided between the cleaner frame 47 and developing device frame 43. By this, the photosensitive drum 11 and the developing roller 18 are urged toward each other with spacer rollers therebetween.
In the electrophotographic image forming apparatus of the process cartridge type, there is a demand is for a large capacity developer (toner) accommodating container and a large removed toner container to extend the time period until the necessity of exchange of the process cartridge.
However, when the capacity of the developer accommodating container is increased, the weight of the developer increases. As a result, the loads imparted to the developing roller and the photosensitive drum are increased correspondingly.
Additionally, the loads change with consumption of the developer. Furthermore, the developer per se adjacent the developing roller 48 are influenced by the weight of the developer.
The present invention is directed to a solution to the problem.
Accordingly, it is a principal object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus wherein the image quality is stabilized even if the accommodation capacity of the developer (toner) is increased.
It is another object of the present invention to provide a process cartridge, an assembling method for the process cartridge and an electrophotographic image forming apparatus in which the load imparted by the weight of a developer to a developing member and an electrophotographic photosensitive drum is reduced.
It is a further object of the present invention to provide a process cartridge, an assembling method for the process cartridge and an electrophotographic image forming apparatus in which the change in the load imparted by the weight of the developer to a process cartridge, the developing member, and the electrophotographic photosensitive drum, can be reduced.
According to an aspect of the present invention, there is provided a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, comprising:
a developing member for developing an electrostatic latent image formed on the electrophotographic photosensitive drum;
a toner accommodation frame having an developer accommodating portion for accommodating a developer to be used by the developing member to develop the electrostatic latent image;
a drum frame for supporting the electrophotographic photosensitive drum;
a developing frame for supporting the developing member, the developing frame being swingably coupled with the toner accommodation frame;
a first end cover connected with the drum frame and the developing frame at one longitudinal end of each of the drum frame and the developing frame; and
a second end cover connected with the drum frame and the developing frame at the other longitudinal end of the drum frame and the developing frame.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.